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Strobilurins A and X, isolated from Mucidula venosolamellata culture extracts, demonstrated potent inhibition of human melanoma G-361 cell proliferation. Strobilurin X exhibited milder inhibitory effects on human fibroblast cells (NB1RGB) compared to strobilurin A. Additional strobilurin-related compounds were isolated from the other mushroom species. Oudemansins A and B displayed weaker activities on G-361 cells than strobilurins A and B, respectively, emphasizing the importance of a conjugated double-bond structure. Among isolated compounds, strobilurin G showed the lowest IC50 value for G-361 cells. Additional strobilurins bearing various substituents on the benzene ring were synthesized. Synthetic intermediates lacking the methyl β-methoxyacrylate group and a strobilurin analogue bearing modified β-methoxyacrylate moiety showed almost no inhibitory activity against G-361 cells. The introduction of long or bulky substituents at the 4′ position of the benzene ring of strobilurins enhanced the activity and selectivity, suggesting differential recognition of the benzene ring by G-361 and NB1RGB cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • R∙+HO 2 ↔ ROOH→R-CHO+H 2 O and R∙+HO 2 → vdw complex → R+3O 2 were added to the mechanism. • The reactive sites of DMF and 2MF were studied. • Improved ignition delay prediction accuracy with updated reaction rate constants. A valuable alternative to traditional fuels, bio-oxygenated fuels provide benefits. Oxygenated fuels 2,5-dimethylfuran (DMF) and 2-methylfuran (2MF) perform well. This study used quantum chemical calculations and combustion simulations to evaluate the combustion characteristics of low and medium temperature combustion mechanisms. Conclusions: In the combustion reaction of DMF and 2MF, the H-abstraction reaction occurs mainly at the methyl site. The reaction between macromolecular radicals and HO 2 at low and middle temperatures plays a critical role in fuel auto-ignition. Thus, R∙+HO 2 ↔ ROOH→R-CHO+H 2 O and R∙+HO 2 → vdw complex → R+3O 2 were added to the mechanism. Modified mechanism improves temperature prediction accuracy. The HOMO-LUMO gap is narrowed by the methyl group, which is closely related to the reaction sites and the molecular structure. After H-abstraction, the methyl site is the most likely to react, followed by the C3 and C5 sites. [ABSTRACT FROM AUTHOR]

Brassinolide (BL) is a possible plant growth regulator in agriculture, but the presence of a steroid skeleton hampers the field application of BL in agriculture because of its high synthetic cost. We discovered NSBR1 as the first nonsteroidal BL-like compound using in silico technology. Searching for more potent BL-like compounds, we modified the structure of NSBR1 with respect to 2 benzene rings and the piperazine ring. The activity of synthesized compounds was measured in Arabidopsis hypocotyl elongation. The propyl group of butyryl moiety of NSBR1 was changed to various alkyl groups, such as straight, branched, and cyclic alkyl chains. Another substituent, F, at the ortho position of the B ring toward the piperazine ring was changed to other substituents. A methyl group was introduced to the piperazine ring. Most of the newly synthesized compounds with the 3,4- (OH)2 group at the A ring significantly elongated the hypocotyl of Arabidopsis. [ABSTRACT FROM AUTHOR]

The separation of CH 4 and N 2 is an important technology for the effective utilization of low-concentration CBM. To improve CH 4 /N 2 separation properties of coal-based porous carbons, Shaanxi long-flame coal was hydrothermally treated followed by KOH activation for the preparation of porous carbons. The impact of hydrothermal treatment on the pore structure and CH 4 /N 2 separation properties of porous carbons was investigated. The results show that hydrothermal decomposes the macromolecular structure of coal, which enlarges the pore size of the raw coal and facilitates the KOH penetrate deeper into the coal particles. Meanwhile, more release of methylene/methyl groups and in-stiu growth of carbon nanotubes develop the pore structure during the activation process of treated coal. The pore structure of porous carbons can be precisely controlled by adjusting the water-coal ratio in the hydrothermal process. Among them, C-TC1.25 shows a 22% increase in CH 4 adsorption capacity over C-RC, which is mainly due to a significant increase in the micropore volume at 0.5–1.0 nm and generation of carbon nanotubes as gas transport channels. At 298 K and 101 kPa, C-TC1.25 exhibits a CH 4 adsorption capacity reaching 1.72 mmol/g, which surpasses that of most known adsorbents, while the IAST selectivity is as high as 5.5. The breakthrough experiment confirms that the porous carbons effectively enable separation of CH 4 /N 2 mixed gas. Kinetic studies show the CH 4 adsorption process on C-TC1.25 conform to the pseudo-first-order model and exhibit surface-attached physical adsorption. [Display omitted] • Hydrothermal was used to improve the CH 4 /N 2 separation of coal-based porous carbons. • CNTs are generated and narrow micropores increase after hydrothermal treatment • CH 4 adsorption capacity and CH 4 /N 2 selectivity are as high as 1.72 mmol/g and 5.5. • Micropores in the range of 0.5–1.0 nm play a major role on the CH 4 /N 2 separation. [ABSTRACT FROM AUTHOR]

• Tannic acid grafted with long-chain alkylamines was used to modify cotton fabrics. • Modification made hydrophobic surfaces of cotton fabrics. • Modified surface has low polar and middle dispersive component of surface energy. • Modified cotton fabrics have high hexane adsorption capacity. Cotton fabrics were modified on surface wettability for efficient oil/water separation. The modification adopted in previous literature are commonly complicated in steps, expensive in chemicals applied, and not environmentally begien in solvents used. This article applied a novel one-step modification protocol to modified cotton fabrics using tannic acid (TA) grafted via Michael addition/Schiff base reactions with long-chain alkylamines, including 1-tetradecylamine (TDA), 1-hexadecylamine (HDA), and 1-octadecylamine (ODA) with 14, 16 and 18 methyl groups, respectively, were applied in this study for cotton fabrics modification. The TA, an inexpensive natural polyphenol, was adopted for providing excess catechol groups for linking the cotton surface and the alkylamines. The grafting reactions via Michael addition/Schiff base reaction were performed at room temperature and pH 8.5 with catalysts CuSO 4 /H 2 O 2 for significantly reducing the reaction time needed. The chemical analysis confirmed the modification of the cotton fabrics to possess hydrophobic surface, with contact angles for water droplets on the modified surface as 133.3o, 136.0o and 142.9° for TA-TDA, TA-HDA, and TA-ODA cotton fabrics, respectively; and diiodinemethane droplets on the modified surface being 56.0o, 58.8o and 59.3o, respectively. The modified cotton surface has intermediate dispersive component of surface energy (29.0–31.2 mJ/m2) and low polar component (4.2–6.2 mJ/m2), yielding high affinity to oil but low affinity to water. Parametric study revealed that the pH value and reaction time are the most important parameters for the alkylamine grafting reactions, while the reduction of catalyst amount used but still with sufficient modification on cotton fabrics can be achieved. The oil absorption tests with cotton fabrics contacting hexane (top)-water (bottom) layers revealed high hexane adsorption capacity: 0.96, 1.22, 1.25 g hexane/g cotton for TA-TDA, TA-HAD and TA-ODA cotton fabrics, respectively. The absorption tests with cotton fabrics contacting water first for 30 s then hexane for another 30 s had much lower absorption capability of hexane: 0.52, 0.85, 0.87 g hexane/g cotton for TA-TDA, TA-HAD and TA-ODA cotton fabrics, respectively, since water would penetrate the major pores for inhibiting further oil absorption. [Display omitted] [ABSTRACT FROM AUTHOR]

A novel conductive polymer poly(aniline-co-thionine) (PANTHI) was prepared via electrochemical polymerization by introducing redox-active thionine into the polyaniline skeleton to extend its cable length, and then explored as a cathode active material for aqueous zinc-polymer batteries in a mixed solution of ZnCl2 and NH4Cl. Due to that thionine is a phenothiazine derivative without methyl groups, it increases the degree of conjugation of copolymer chains and the Zn-copolymer battery exhibits greatly enhanced discharge specific capacity, energy density, and excellent cycle stability at pH 4.8, compared to Zn-polyaniline batteries. The Zn-PANTHI battery delivers a high specific capacity and energy density of 157.8 Ah kg-1 and 173.6 Wh kg-1, respectively, and retains the coulomb efficiency of about 95.3% over 200 consecutive cycles at a current density of 200 mA g-1. The copolymerization strategy provided an effective method towards synthesizing new conductive aniline-based polymers with other organic redox-active groups for rechargeable batteries, supercapacitors and sensors. [ABSTRACT FROM AUTHOR]

DAMASCENOLIDETM [1, 4-(4-methylpent-3-en-1-yl)furan-2(5H)-one], which has a citrus-like odor, is an important aroma component of roses. We have previously reported on the synthesis and odor evaluation of double-bond isomers of 1 and concluded that the position and the geometric isomerism of the double-bond had a significant effect on the odor. For the purpose of deepening knowledge about structure–odor relationships, we synthesized 13 analogs of compound 1 and evaluated their odors. As a result, it was found that the presence of two double-bonds and branched methyl group at the terminal position in the side chain was essential in order to have a citrus-like odor. Substitution of the side chain with appropriate length at the appropriate 4-position of the 2(5H)-furanone ring was also an important factor in determining the quality of the odor. Synthesis and odor evaluation of 13 analogs of DAMASCENOLIDETM were achieved. [ABSTRACT FROM AUTHOR]

Long-term exposure to arsenic, a common environmental pollutant, can induce various types of liver injury, but the mechanism and treatment measures remain unclear. This study constructed a rat model of arsenic-induced liver injury, with methyl group donor S -adenosylmethionine (SAM) supplementation and Rosa roxburghii Tratt juice intervention, to explore the epigenetic mechanism and intervention method of arsenic-induced liver injury from the perspective of hepatic bile acid metabolism. The results showed that arsenic exposure induced the accumulation of total bile acids (TBA) in the liver and serum of rats, and the abnormalities in liver function and liver histopathology. Arsenic reduced histone H3K36 trimethylation (H3K36me3) in the liver via consuming methyl group donor SAM. The reduction of H3K36me3 was involved in arsenic-induced bile acid accumulation by inhibiting the transcription of negative feedback regulators Fxr and Fgfr4 for hepatic bile acid synthesis. SAM supplementation reversed arsenic-induced bile acid accumulation and liver injury by reactivating H3k36me3-dependent transcription of Fxr and Fgfr4. Moreover, this study found that Rosa roxburghii Tratt juice could rescue arsenic-induced SAM consumption, recover H3K36me3-dependent negative feedback regulation of hepatic bile acid synthesis, and alleviate arsenic-induced bile acid accumulation and liver injury. In conclusion, arsenic exposure perturbed H3K36me3-dependent hepatic bile acid metabolism via depleting SAM, thereby inducing hepatic bile acid accumulation and liver injury, which was ameliorated by the supporting effect of Rosa roxburghii Tratt juice on SAM. This study contributes to understanding the mechanism of arsenic-induced liver injury from the perspective of SAM-dependent epigenetics, providing new insight into its prevention and treatment. Arsenic exposure consumes methyl group donor SAM, reducing histone H3K36 trimethylation (H3K36me3) levels and inhibiting H3K36me3-dependent transcriptional activation of negative feedback regulators Fxr and Fgfr4 for hepatic bile acid synthesis, thereby inducing bile acid accumulation and subsequently liver injury by promoting bile acid synthesis. Rosa roxburghii Tratt blocks this process by rescuing arsenic-induced consumption of SAM. [Display omitted]. • Arsenic-induced SAM depletion causes bile acid disorder and liver injury. • Arsenic-induced SAM depletion inhibits epigenetic dependent bile acid metabolism. • Rosa roxburghii Tratt alleviates arsenic-induced bile acid disorder and liver injury. • Rosa roxburghii Tratt rescues SAM depletion and aberrational epigenetic regulation. [ABSTRACT FROM AUTHOR]

Abstract The bulk presence of methyl orange is contributed by anthropogenic sources which poses substantial threat to health and the environment. Locally isolated Rhodococcus strains were used as alternatives to develop greener and cost effective methyl orange removal technology. Rhodococcus strain UCC 0004 in particular demonstrated complete removal of 0.5 g/L methyl orange after 2 days of incubation and this strain exhibited 513% higher methyl orange removal efficiency under static mode in comparison to agitated mode. Adopting the technology of immobilization enabled the decolourization of higher concentration of methyl orange which resulted in 66% greater methyl orange removal activity as opposed to the non-immobilized cells. Optimization of immobilization parameters at 0.4% (w/v) alginate concentration, 0.3 M CaCl 2 , 3 mm bead diameter and 50 beads led to improved methyl orange-decolourizing activity and reduced the time taken to achieve complete decolourization by 67%. The immobilized beads could be reused up to nine batches without significant loss of methyl orange-decolourizing ability which is advantageous economically. The immobilized cells demonstrated higher substrate affinity (K m = 0.3771 g/L) and accelerated rate of disappearance of methyl orange (V max = 0.05903 g/L/h) compared to free cells. No germination inhibition was observed on Triticum aestivum and Vigna radiata indicating complete removal of dye toxicity. The decolourization of methyl orange occurred through biodegradation as supported by complete disappearance of the major peak from UV–vis spectrum. Therefore, this strain has a huge potential to be developed as biological tool for efficient removal of wastewater containing methyl orange. Highlights • Novel Rhodococcus strain UCC 0004 is competent in decolourizing 0.5 g/L methyl orange after 2 days of incubation. • Methyl-orange decolourizing activity is significantly improved upon immobilization and could be reused for nine cycles. • The strain could tolerate high concentration of 10 g/L methyl orange in its immobilized form. • The treated solution has negligible toxicity and can be used for irrigation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Corrosion inhibiting of imidazole derivatives on aluminum was theoretically analyzed. • Neutral species can chemisorb or physisorb on the Al(1 1 1) surface. • Protonated species can only physisorb on the surface. • Methyl group increase adsorption capacity of imidazole molecule. The corrosion inhibiting effect of imidazole derivatives on aluminum was studied using density functional theory (DFT) calculations to assess the relationship between molecular structures and their corresponding efficiencies. The chemical reactivity of the neutral and protonated species (IM, Me-IM, IMH+ and Me-IMH+) was investigated, and the impact of methyl group substitution on the adsorption ability onto Al(1 1 1) surface was examined. Results revealed that the neutral species can be absorbed onto Al(1 1 1) surface by forming covalent bond N–Al, implying chemisorption as the mechanism of adsorption. It was also established that, the IMH+ and Me-IMH+ can be adsorbed via the Cl− anion, which was already firstly adsorbed onto the Al(1 1 1) surface. The DFT calculations align well with the experimental results, suggesting that introduction of a methyl group at the 2-position of the imidazole ring enhances the adsorption ability. [ABSTRACT FROM AUTHOR]

Bacterial wilt, caused by Erwinia tracheiphila (Smith), can result in serious yield loss of cantaloupe in the Midwest United States. Although neonicotinoid insecticides are an effective means of managing the cucumber beetles that vector E. tracheiphila , this management regime may cause toxicity to pollinators. An alternative method of managing this disease is to use products that induce resistance. Over four years, we have compared disease severity of bacterial wilt, cucumber beetle numbers, feeding damage and yield as influenced by products purported to induce Systemic Acquired Resistance (SAR) or Induced Systemic Resistance (ISR). Acibenzolar-S-methyl (Actigard ® ) effectively lowered disease severity of bacterial wilt in years when disease pressure was moderate or high. Actigard ® was also associated with lower levels of cucumber beetle feeding in some years. However, when disease pressure was low, Actigard ® at some rates and timings, caused yield loss. The other products, Regalia ® and Serenade Max ® , are purported to elicit ISR and did not consistently lower disease levels or influence beetle feeding in the current study. The standard insecticide regime, imidacloprid used as a drench at planting and permethrin applications at weeks 3–6, was the most consistent method of lowering beetle feeding and thus managing bacterial wilt. Since Actigard ® could be associated with yield loss, its use for the management of bacterial wilt in cantaloupe cannot be recommended. [ABSTRACT FROM AUTHOR]

20% commercial suspension emulsion (SE) of (8% tetraconazole + 12% kresoxim-methyl), as a pre-registered product in China, was firstly investigated under Chinese greenhouse-field conditions. A MWCNTs-based QuEChERS method for simultaneous determination of tetraconazole and kresoxim-methyl in strawberry was developed and validated via RRLC-QqQ-MS/MS. On basis of this method, the dissipation behaviours, residue distributions and dietary risk probability of these fungicides in strawberry were further investigated for food safety. The dissipations of tetraconazole and kresoxim-methyl followed first-order kinetics with the half-lives of 8.0–18.2 days. The highest residues (HRs) of these fungicides in the supervised trials at the pre-harvest interval (PHI, 3 days) were below 0.8970 mg kg −1 . The total national estimated daily intake (NEDI) of tetraconazole and kresoxim-methy in strawberry at the PHI 3 day was 0.2784 mg and 0.4031 mg, respectively, based on Chinese dietary pattern and terminal residue distributions under good agricultural practices (GAP) conditions. The risk quotients (RQs) of tetraconazole and kresoxim-methy at PHI 3 days were below 82.7% and 1.6%, respectively, showing that the evaluated strawberry exhibited an acceptably low dietary risk to consumers. The current study could not only guide reasonable usage of the formulation, but also facilitate the setting of maximum residue limits (MRLs) of tetraconazole in strawberry. [ABSTRACT FROM AUTHOR]

A series of rare earth elements (La, Ce and Pr) modified HZSM-5 catalysts were synthesized by incipient-wetness impregnation method and then characterized by XRD, N 2 adsorption–desorption, SEM, CO 2 -TPD, NH 3 -TPD, and FT-IR measurements. Their catalytic behaviors toward methyl mercaptan decomposition reactivity were investigated. The results indicated that rare earth modified HZSM-5 catalysts demonstrated improved catalytic activity, which significantly reduced the reaction temperature for complete conversion of CH 3 SH, and La modified HZSM-5 catalyst exhibited higher activity than Ce and Pr doped HZSM-5 catalysts. CH 3 SH can be almost completely converted over 5%La/HZSM-5 at 450 °C compared to pure HZSM-5 at 600 °C. Moreover, 5%La/HZSM-5 showed high stability and no notable deactivation was observed during 30 h on stream. The improvement in catalytic performance can be attributed to the regulated acid–base properties of the HZSM-5 catalysts by rare earth metal doping. Comparisons between spent HZSM-5 and spent La doped HZSM-5 catalysts were done using Raman and TG techniques. Furthermore, the optimal loading amount of La was investigated, and 9 wt% and 13 wt% La/HZSM-5 catalysts exhibited better catalytic activity. [ABSTRACT FROM AUTHOR]

Monomethylarsonic acid (MMA) is an important arsenic pollutant that was extensively used as a herbicide/pesticide. Once introduced to the environment, MMA can enter the food chain or be recycled to the more mobile forms of arsenic that can contaminate nearby water sources. Density functional theory with dispersion corrections (DFT-D3) calculations provide a molecular-level understanding of the fate of pollutants such as MMA, particularly their interactions with reactive soil components such as iron (oxyhydr)oxides. Energies, optimal geometries, and vibrational frequencies for hydrated MMA complexes with iron (oxyhydr)oxide clusters were computed and ligand exchange reactions were constructed to investigate the thermodynamics of inner- and outer-sphere complex formation. The Gibbs free energies and enthalpies of adsorption show that both inner- and outer-sphere complex formation is thermodynamically favourable, with monodentate complexes being most favourable. The calculated As Fe inter-atomic distances for MMA complexes are shown to be 3.23–3.55 Å for inner-sphere complexes and 5.17–5.75 Å for OS complexes. The calculated infrared frequencies were correlated to experimental values in the 740–900 cm −1 range containing stretching frequencies of As O bonds. A comparison between MMA and other organoarsenicals reveals that adding methyl groups to arsenate affects the adsorption process and hence the mobility of organoarsenicals in the environment. [ABSTRACT FROM AUTHOR]

Vibrio cholerae can colonize the gastrointestinal track of humans and cause the disease cholera. During colonization, the alternative sigma factor, RpoS, controls a process known as “mucosal escape response,” defining a specific spatial and temporal response and effecting chemotaxis and motility. In this report, the expression and proteolytic control of RpoS in V. cholerae was characterized. To date, aspects of proteolysis control, the involved components, and proteolysis regulation have not been addressed for RpoS in V. cholerae . Similar to Escherichia coli , we find that the RpoS protein is subjected to regulated intracellular proteolysis, which is mediated by homologues of the proteolysis-targeting factor RssB and the protease complex ClpXP. As demonstrated, RpoS expression transiently peaks after cells are shifted from rich to minimal growth medium. This peak level is dependent on (p)ppGpp-activated rpoS transcription and controlled RpoS proteolysis. The RpoS peak level also correlates with induction of a chemotaxis gene, encoding a methyl-accepting chemotaxis protein, earlier identified to belong to the mucosal escape response pathway. These results suggest that the RpoS expression peak is linked to (p)ppGpp alarmone increase, leading to enhanced motility and chemotaxis, and possibly contributing to the mucosal escape response. [ABSTRACT FROM AUTHOR]

Volatile primary aromatic benzyl alcohol (BzOH) reacts with strong atmospheric oxidants like OH, Cl, NO 3 radicals. The present study elucidates detailed investigation of gas phase reaction mechanisms of benzyl alcohol with NO 3 radicals using density functional theory at M06-2X/6-311+G(d,p) and MPW1K/6-311+G(d,p) levels. The results show that the H-abstraction from methyl group is more energetically favorable with small barrier height. Single-point energy calculations were also performed at the CCSD(T)/6-311+G(d,p) level of theory. The spin state analysis (singlet, triplet) concludes ground state (singlet) reactions are feasible. The reaction force profile along the reaction path is rationalized in terms of structural and electronic rearrangements that take place during the chemical transformation. From the reaction force analysis, it is evident that structural rearrangement plays more dominant role than electronic reordering in this reaction. The calculated rate constant of H-atom abstraction from methyl group of benzyl alcohol with NO 3 radical is 16.72 × 10 −15 cm 3 molecule −1 s −1 , which is in good agreement with experimental study. Overall, NO 3 will replace OH and play a major role in reaction with BzOH during night time. [ABSTRACT FROM AUTHOR]

Silica membranes possess gas separation characteristics, but their undesirable performances and poor hydrothermal stabilities hinder the application in industrial gas treatments. To solve the problems, we have devised a new membrane preparation method involving methyl group modification and nickel-cobalt doping. In this paper, methyl-modified silica (MSiO 2) and nickel-cobalt-doped methyl-modified silica (Ni x Co 0.08−x /MSiO 2 , x = 0, 0.024, 0.04, 0.056 and 0.08) materials and membranes were synthesized using the sol-gel technique. The physical-chemical properties of materials were characterized by FTIR, XRD, TEM, N 2 adsorption-desorption and SEM. The H 2 permeances and permselectivities of membranes were evaluated with pressure difference, temperature, Ni/Co content and hydrothermal stability as the inferred factors. In Ni-Co/MSiO 2 materials, nickel and cobalt elements were found in the form of Si-O-Ni/Si-O-Co bonds and NiO/CoO. The H 2 permeance and H 2 /CO 2 permselectivity of the Ni 0.024 Co 0.056 /MSiO 2 membrane were 7.6 × 10−7 mol m−2 Pa−1 s−1 and 113.5, respectively, which were 2.1 and 2.8 times higher than the MSiO 2 membrane at 0.3 MPa and 200 °C. After steam treatment and regeneration, the Ni 0.024 Co 0.056 /MSiO 2 membrane increased from the original values in the H 2 permeance and H 2 /CO 2 permselectivity, while the MSiO 2 membrane decreased. The final results revealed that Ni-Co/MSiO 2 membranes possessed excellent H 2 /CO 2 permselectivity and hydrothermal stability. [Display omitted] • Methyl-modified silica (MSiO 2) and nickel-cobalt-doped methyl-modified silica (Ni-Co/MSiO 2) materials and membranes were synthesized under N 2 atmosphere. • The physical-chemical properties of materials were characterized by FTIR, XRD, TEM, N 2 adsorption-desorption and SEM. • The H 2 permeances and permselectivities of membranes were evaluated with pressure difference, temperature, Ni/Co content and hydrothermal stability as the inferred factors. • The Ni-Co/MSiO 2 membranes possessed excellent H 2 /CO 2 permselectivity and hydrothermal stability. [ABSTRACT FROM AUTHOR]

1-Fluoro-pentane-2,4-dione (monofluoroacetylacetone, MFAA) is an asymmetric β-diketone with a strong intramolecular hydrogen bond similar to acetylacetone (AA) and its fluorinated analogs 1,1,1-trifluoro-(TFAA), and 1,1,1,5,5,5-hexafluoroacetylacetone (HFAA). The presence of a fluorine atom in MFAA has the potential to open an HF elimination channel in its gas-phase photochemistry motivating this study of MFAA hydrogen bonding by computer modeling using Density Functional Theory (DFT). As a context, we also report DFT modeling of AA and selected fluorinated acetylacetones: 1,1-difluoro-pentane-2,4-dione (difluoroacetylacetone, DFAA), TFAA, and HFAA. The most stable molecular structure for all three asymmetric β-diketones (MFAA, DFAA and TFAA) is the isomer with the fluoromethyl group proximal to the carbonyl carbon; in comparison to the proton transfer isomer, which has the fluoromethyl group proximal to the hydroxyl carbon, the carbonyl isomer is lower in energy by 5.1–5.5 kJ mol −1 (B3LYP/cc-pVTZ) and 2.1–3.7 kJ mol −1 (MP2/Aug-cc-pVTZ). We also report hydrogen bond strengths, barriers to proton transfer interconversion and barriers to rotation of the methyl/fluoromethyl groups. Our study, the first to report molecular structure information on MFAA and DFAA, indicates that the most stable chelated isomer of MFAA is not the structure with the strongest hydrogen bond as conventionally determined. Our modeling also reveals a coupling between proton transfer isomerization and methyl group rotation, and an unexpected double-minimum potential for the rotation of the fluoromethyl group of MFAA. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO 2) absorption into aqueous amine solvents is known to be governed by two competing reactions leading to carbamate or bicarbonate formation. Sterically hindered alkanolamines with different degrees of methylation are experimentally known to cause different favorability in forming carbamate or bicarbonate. However, the fundamental mechanisms responsible for the preferential formation of carbamate or bicarbonate still remain unclear. Herein, we present CO 2 absorption behavior with several different sterically hindered amines, especially the effects of methylation and temperature. Our ab initio metadynamics simulations clearly demonstrate that free-energy barriers for the carbamate and bicarbonate formation reactions strongly depend on the degree of steric hindrance of hydrophobic methyl groups. This in turn directly impacts on the kinetic favorability of the two competing reaction pathways. Our analysis shows that various degrees of steric effects cause considerably different temperature-dependent degrees of solvation of the nitrogen atom of hindered amines, which may directly affect CO 2 accessibility to form carbamate. Moreover, the enhanced solvation as a result of increased steric effects particularly at low absorption temperatures lead to kinetically facile protonation of the nitrogen atom of amines, initiating and promoting bicarbonate formation. Our work sheds light on the effects of various degrees of steric hindrance, with different temperature-dependent solvation degrees governing reaction mechanisms and rates during CO 2 capture. • CO 2 absorption rates and mechanisms are governed by temperature-dependent steric effects. • Degree of steric hindrance of hydrophobic methyl groups play a crucial role. • Steric effects directly affect CO 2 accessibility to form carbamate. • Increased steric effects facilitate amine protonation, promoting bicarbonate formation. • Improved understanding provides vital hints on how to design advantaged amines for CO 2 capture. [ABSTRACT FROM AUTHOR]

Target spot, caused by Corynespora cassiicola , is among the main disease that may reduce cucumber yield in worldwide. However, few target spot control strategies have been evaluated. The study aimed to evaluate the effect of fungicides in controlling C. cassiicola in vitro and cucumber target spot in a greenhouse. The effect of seven and thirteen fungicides in conidial germination and mycelial growth, respectively, of three pathogen isolates was evaluated in culture medium. The most efficient fungicides in vitro were applied on cucumber plants, at the recommended commercial dose. After three or seven days of the preventive treatment, plants were sprayed with suspensions of the pathogen (104 conidia/mL). For the curative treatment, plants were inoculated 24 h before receiving the fungicide. Evaluation included target spot severity, number and diameter of lesions and sporulation on the leaf. Fungicides of the groups Methyl Benzimidazole Carbamates (MBC) and Quinone outside Inhibitors (QoI) were inefficient (EC 50 > 100 μg/mL) in inhibiting the pathogen in vitro. Chlorothalonil, metiram, boscalid, difenoconazole, epoxiconazole, tebuconazole, and flutriafol showed EC 50 < 1 or 1–10 μg/mL. Chlorothalonil, metiram + pyraclostrobin, boscalid + kresoxim-methyl, and azoxystrobin + benzovindiflupyr controlled the disease, providing greater severity reduction as preventive treatment, without any difference between the two application times. The number and diameter of lesions decreased when fungicides were applied as preventive treatment. Chlorothalonil reduced the number of lesions in curative treatment, while fluxapyroxad + pyraclostrobin, azoxystrobin + benzovindiflupyr, boscalid + kresoxim-methyl, and difenoconazole decreased the diameter of lesions. Sporulation on the leaves also reduced, especially when fungicides were preventively employed. A preventive management is recommended in areas with frequent reports of target spot outbreaks, adopting the alternation of the four most efficient fungicides in controlling the disease in order to reduce possible emergence of resistant isolates of the pathogen to the site-specific fungicides boscalid and benzovindiflupyr. • Importance of chemical control of cucumber target spot to be preventive. • Fungicides of the groups MBC and QoI were inefficient in inhibiting the pathogen. • Corynespora isolates from cucumber are resistant to MBC and QoI fungicides. • Epidemiological aspects of target spot affected by fungicides. [ABSTRACT FROM AUTHOR]

Electrochemical behavior of three biologically important triazole and phenol containing Schiff bases (E)-3-((4H-1,2,4 triazol-4- ylimino) methyl)benzene-1,2-diol (TMB), (E)-3-((4H-1,2,4 triazol-4-ylimino) methyl)para-phenol (p-TMP) and (E)-3-((4H-1,2,4 triazol-4-ylimino) methyl)ortho-phenol (o-TMP) were investigated by electrochemical, spectroscopic and computational methods. The peak potential of all the three compounds showed a linear dependence on pH under acidic conditions, but under alkaline conditions, electron transfer was not coupled to proton transfer. The acid-base dissociation constant (pKa) values of the compounds were evaluated both by electrochemical and UV-Vis spectroscopic techniques. On the basis of experimental and theoretical findings, redox mechanisms of the compounds were proposed and certain important kinetic and thermodynamic parameters were determined from their temperature and pH responsive redox response. Our studies showed a) low cytotoxicity for all three triazoles and b) antioxidant properties of these triazoles. TMB was found as the most promising antioxidant, which makes this compound interesting as a basis for further development as food supplement. [ABSTRACT FROM AUTHOR]

Two modified imidazole bases (1-heptyl-2-methyl-imidazole and 1-dodecyl-2-methyl-imidazole) were synthesized, each with a long alkyl chain (7 or 12 carbon) attached to the N-3 position. Anion exchange membranes (AEMs) were prepared with imidazolium cations derived from these bases that were either grafted directly onto the benzyl position of poly(phenylene oxide) (PPO) or affixed to the PPO using a hexyl spacer chain. First, we reacted 1-methylimidazole with brominated PPO and with PPO with a hexyl spacer chain. By comparing the alkaline stability of the resultant AEMs, we demonstrated that a hexyl spacer chain could improve AEM alkaline stability substantially. Second, by comparing the alkaline stability of PPO-based AEMs obtained by the reaction of brominated PPO with 1-methylimidazole and 1,2-dimethylimidazole, we showed that C-2-substituted (with a methyl group) imidazolium-based AEMs were much more stable in alkali than C-2-unsubstituted imidazolium-based AEMs. Finally, by investigating the alkaline stability of AEMs synthesized by reaction of brominated PPO with 1,2-dimethylimidazole and modified imidazole bases (with 7 or 12 alkyl carbon chain at the N-3 position), we demonstrated that the increase in length of a long alkyl chain affixed to the N-3 position decreases the alkaline stability of the resultant imidazolium-based AEMs. [ABSTRACT FROM AUTHOR]

Present research discussed the utilization of aminated pumpkin seed powder (APSP) as an adsorbent for methyl orange (MO) removal from aqueous solution. Batch sorption experiments were carried to evaluate the influence of pH, initial dye concentration, contact time, and temperature. The APSP was characterized by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The experimental equilibrium adsorption data were fitted using two two-parameter models (Langmuir and Freundlich) and two three-parameter models (Sips and Toth). Langmuir and Sips isotherms provided the best model for MO adsorption data. The maximum monolayer sorption capacity was found to be 200.3 mg/g based on the Langmuir isotherm model. The pseudo-first-order and pseudo-second-order model equations were used to analyze the kinetic data of the adsorption process and the data was fitted well with the pseudo-second-order kinetic model ( R 2 >0.97). The calculated thermodynamic parameters such as Δ G 0 , Δ H 0 and Δ S 0 from experimental data showed that the sorption of MO onto APSP was feasible, spontaneous and endothermic in the temperature range 298–318 K. The FTIR results revealed that amine and carboxyl functional groups present on the surface of APSP. The SEM results show that APSP has an irregular and porous surface which is adequate morphology for dye adsorption. Desorption experiments were carried to explore the feasibility of adsorbent regeneration and the adsorbed MO from APSP was desorbed using 0.1 M NaOH with an efficiency of 93.5%. Findings of the present study indicated that APSP can be successfully used for removal of MO from aqueous solution. [ABSTRACT FROM AUTHOR]

The present study investigated the application of the LiFePO 4 (LFP) cathode material for lithium ion batteries as a photocatalyst in the photodegradation of methyl orange (MO) by oxalic acid (Oxa, H 2 C 2 O 4 ). The photocatalytic role of LFP for different initial pH values as well as different concentrations of LFP, Oxa, and MO was examined. The results show that, while the decomposition of MO by either LFP or Oxa under ultraviolet light is difficult, MO removal is significantly enhanced when both LFP and Oxa coexist in the reaction system. In particular, high initial concentrations of Oxa and LFP appear to be beneficial for the degradation of MO. The optimal MO degradation efficiency was achieved at pH 4. The role of photoproduction intermediates was also investigated. Scavenging experiments using tertiary butyl alcohol, an · OH-specific radical scavenger, and l -histidine, a universal radical scavenger, corroborated the suggestion that other oxidative free radicals besides · OH are also involved in the MO degradation. A possible reaction mechanism for the photocatalytic degradation of MO by LFP and Oxa was proposed. This study thus provides a direct route for the reutilization of the cathode material LFP as a photocatalyst in the photodegradation of organic contaminants by low-molecular weight organic acids. [ABSTRACT FROM AUTHOR]

Sufficient dietary fibre intake reduces the risk of several diseases, but the mechanisms linking fibre structure and health effects remain unclear. To analyse the influence of the amount of methyl groups esterified to the backbone, lemon pectins of different degrees of methyl esterification (30, 56, and 74DM) were studied for immune receptor activating potential and epithelial barrier protection. In reporter assays, the pectins demonstrated TLR/MyD88 dependent activation of NF-κB/AP-1, which increased with increasing pectin DM. To analyse the importance of backbone structure, the pectins were enzymatically digested into oligomers, which abrogated TLR activating potential. The 30 and 74DM pectins induced strong protection of the epithelial barrier measured by T84 transepithelial electrical resistance (TEER). These results indicate that activation of immune cells by lemon pectins is TLR dependent, and the intact polymer backbone is indispensable for activation. In addition, DM is a determining factor in activating potential and epithelial barrier protective effects. [ABSTRACT FROM AUTHOR]

In this study a clinoptilolite zeolite was modified by an ionic liquid 1-hexadecyl-3-methylimidazolium chloride monohydrate to 1.0 and 2.0 times its external cation exchange capacity (ECEC). The ionic-liquid-crafted zeolite (ILCZ) was tested for its removal of anionic dyes from solution using methyl orange (MO) as an example. The uptake of MO was fast and followed a pseudo-second-order kinetics with MO adsorption capacities of 45 and 116 mmol/kg on ILCZ modified to 1.0 and 2.0 ECEC, respectively. Stoichiometric desorption of counterion chloride accompanying MO uptake suggested an anion exchange mechanism of MO uptake on ILCZ modified to 2.0 ECEC. Solution pH in the range of 2–11 and ionic strength in the range of 0.001–0.01 M of background salt concentrations of varying charges had minimal effects on MO uptake, suggesting higher affinity of MO for ILCZ in comparison to other inorganic anions. As the MO adsorption capacity on ILCZ modified to 2.0 ECEC was about the same as the ECEC of the zeolite, the mechanism of removal of anionic dyes was attributed to surface anion exchange resulted from the positively charged ILCZ surfaces due to a bilayer IL formation on zeolite after being modified to 2.0 ECEC. In contrast, patchy admicelles of IL would form on zeolite after being modified to 1.0 ECEC, resulting in reduced MO uptake. The contrasting behaviors of IL modification on zeolite and subsequent MO adsorption on ILCZ suggested that modification of ILCZ to 2.0 ECEC was necessary for ILCZ to serve as a sorbent material for the removal of anionic dyes from solution. [ABSTRACT FROM AUTHOR]

This study shows the influence of a 5-methyl substituent on the interaction between 1-methylcytosine, 1,5-dimethylcytosine, 1-methyluracil and 1-methylthymine and dichloride (Cl 2 ) and fluorine chloride (ClF). The methyl derivatives were selected because of the important role played by a methyl group at position 5 of the pyrimidine ring on the biological properties of nucleobases. Besides binding energies obtained at the MP2/aug-cc-pVDZ level, a variety of theoretical methods were used to analyze the structures of the different minima obtained. A total of 116 complexes have been studied. [ABSTRACT FROM AUTHOR]

Although H-abstraction reactions from methanol by methyl radical (CH 3 ), triplet methylene radical ( 3 CH 2 ) and formyl radical (HCO) are important for methanol pyrolysis and combustion, the kinetic mechanisms of those reactions are indistinct and need to be better understood. Ab initio calculations were performed to optimize geometries of transition states using Gaussian 09W package with the B3LYP density functional at the 6-311++G (3 df , 3 pd ) basis set. Energy barrier and minimum energy path (MEP) on the reaction potential energy surface were calculated with MP2 method at the same basis set. The canonical variational transition state theory (CVT) with Eckart tunneling correction were employed to compute rate constants over the temperature range 298–2000 K. Results show that, for reaction CH 3 OH + CH 3 , barrier height for hydroxymethyl channel (R1a) is 12.59 kcal/mol and for methoxyl channel (R1b) is 13.82 kcal/mol. Rate constants for channels R1a and R1b are k 1 a = 3.635 × 10 −31 T 5.58 exp(−1962/ T ) cm 3 molecule −1 s −1 , k 1 b = 4.342 × 10 −28 T 4.61 exp(−4284/ T ) cm 3 molecule −1 s −1 , respectively. For reaction CH 3 OH + 3 CH 2 , barrier heights for hydroxymethyl channel (R2a) and methoxyl channel (R2b) are 7.68 kcal/mol and 9.19 kcal/mol, respectively. Rate constant for channel R2a is k 2 a = 5.885 × 10 −28 T 4.19 exp(−1813/ T ) cm 3 molecule −1 s −1 and for channel R2b is k 2 b = 2.266 × 10 −28 T 4.26 exp(−2833/ T ) cm 3 molecule −1 s −1 . For reaction CH 3 OH + HCO, barrier heights for hydroxymethyl channel (R3a) and methoxyl channel (R3b) are 21.88 kcal/mol and 28.83 kcal/mol, respectively. Rate constant for channel R3a is k 3 a = 8.156 × 10 −38 T 7.37 exp(−4900/ T ) cm 3 molecule −1 s −1 and for channel R3b is k 3 b = 2.007 × 10 −27 T 4.34 exp(−11,605/ T ) cm 3 molecule −1 s −1 . This study is beneficial for improving the kinetic mechanism of methanol pyrolysis and combustion. [ABSTRACT FROM AUTHOR]

This study investigates the nitrate radical oxidation of methyl vinyl ether (CH 2 CHOCH 3 , MVE) by quantum chemical methods. The oxidation initiates with the formation of open-cyclic NO 3 -adducts, followed by a series of unimolecular decomposition or bimolecular reactions. Kinetic data suggest that pressure and temperature have strong influence on the environmental fate of MVE. Under atmospheric condition, methyl formate, formaldehyde and NO 2 are the main products by association with O 2 /NO. At low pressure (<50 Torr) 2-methoxyoxirane and NO 2 are main products by decomposition. Total rate coefficient of the bimolecular reaction exhibits negative dependence on temperature (200–300 K) and positive dependence on pressure (1–7600 Torr). The calculated rate coefficient (7.09 × 10 −13 cm 3 molecule −1 s −1 ) is in well agreement with experimental data at 293 K and 760 Torr. [ABSTRACT FROM AUTHOR]

Here, the electrochemical incineration of methyl green (MG), a toxic triarylmethane dye, had been initially performed using boron-doped diamond anode under galvanostatic conditions. The individual and interaction effects of four operating variables (flow rate, applied current density, sulfate concentration and initial MG concentration) on mineralization efficiency were investigated with the aid of Doehlert experimental design. Among the independent variables, sulfate concentration displayed the most interesting roles on MG degradation. Optimum MG degradation was achieved by applying a flow rate of 350 ml/min, applied current density of 7.75 mA/cm 2 , 5.0 mM Na 2 SO 4 , and initial MG concentration of 200 mg/dm 3 at 120 min of electrolysis, being reduced color by 100% and TOC by 80.1%. In addition, the reaction intermediates were properly identified by LC/MS analysis and a plausible reaction sequence was proposed. [ABSTRACT FROM AUTHOR]

Polyurethane (PU) damping materials were prepared by mixed-base PU prepolymers and 4,4′-methylene- bis-(2-chloroaniline) (MOCA) as chain extender. The prepolymer was synthesized from poly(hydroxypivalyl hydroxypivalate succinate) (PHPS) or polypropylene glycol 2000 (PPG-2000) with 2,4-toluene diisocyanate (TDI-100), respectively. The structure, morphology, and dynamic and static mechanical properties were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning tunneling microscopy (STM), dynamic mechanical thermal analysis (DMA), and tensile testing machine, respectively. The results indicated that the mass ratios of polyester prepolymer (PESP) and polyether prepolymer (PETP) ( mPESP/ mPETP ratio) had significantly affected the dynamic mechanical properties of the PUs. When the mPESP/ mPETP ratio was 40/60 and 45/55, and PUs had the temperature range (Δ T) higher than 60°C for efficient loss factor (tan δ>0.4) in the DMA curve with bimodal. The phase diagrams of STM indicated that more complex combination of hard and soft segments existed in the PUs, and the segments of PESP and PETP formed irregular block structures. Furthermore, the mechanical properties of PUs were of higher value. It is believed that PUs may be used as potential damping materials. [ABSTRACT FROM AUTHOR]

Pyridine Boron Trifluoride (PBF)-based electrolyte additive blends for Li[Ni0.42Mn0.42Co0.16]O2 (NMC442)/graphite pouch cells have been systematically investigated. Other additives investigated in the blends included methylene methane disulfonate (MMDS) and ethylene sulfate (DTD). Ultra-high precision coulometry (UHPC), electrochemical impedance spectroscopy (EIS), gas evolution and long-term cycling experiments were made. The results obtained in this work indicate that MMDS and DTD have good compatibility with PBF-type additives and some of their combinations showed significant improvements in coulombic efficiency, reducing impedance and maintaining good capacity retention during high-voltage cycling compared to PBF-type additives alone. [ABSTRACT FROM AUTHOR]

The start-up efficiency of an anaerobic sequencing batch reactor (ASBR) fed with increasing methyl orange (MO) concentrations (from 25 mg l −1 to 500 mg l −1 ) were investigated in this study. The relationship between MO decolorization capacity and the microbial community structure was evaluated. More than 85% of COD and 75% of MO were removed during the whole operation period. However, little methane was generated, due to the successful competition of azo reduction over sulfate reduction and methanogenesis. The scanning electron microscopy and denaturing gradient gel electrophoresis analysis showed a significant variation of the microbial community composition with MO concentration increase. The thresholds of structural and functional disturbances were similar, suggesting a good correlation between degradation performance and community structure. Phylogenetic analysis indicated that Sulfuricurvum and Anaerolineaceae family were the most abundant microorganisms in ASBR responsible for MO decolorization. Batch experiments indicated that acclimated sludge could also use quinoide and Fe(III) as the electron acceptors, thus allowing an efficient reduction of azo dye. [ABSTRACT FROM AUTHOR]

We conducted a study on the transport properties of an ionic liquid 4-(2-methoxyethyl)-4-methylmorpholin-4-ium bis(trifluoromethylsulfonyl)amide ( [MorMEOM][TFSI] ) and lithium bis(trifluoromethanesulfonyl) imide (LiTFSI)-doped [MorMEOM][TFSI] at various temperature and atmospheric pressure states through conductivity, viscosity, and self-diffusion coefficient characterizations. Based on the Walden rule, the α values of neat [MorMEOM][TFSI] and LiTFSI-doped [MorMEOM][TFSI] estimated from the slopes of Walden plots were compared to those calculated from E a , Λ / E a , η . The diffusion coefficients of 1 H, 19 F and 7 Li were determined using the PGSE-NMR method to carry out a study of the dynamics of the cations, anions, and ion pairs. All of the neat [MorMEOM][TFSI] and LiTFSI-doped [MorMEOM][TFSI] gave approximately straight lines for change in the D with Tη −1 , demonstrating that the Stokes–Einstein equation holds for the ionic diffusivity in the ILs. [ABSTRACT FROM AUTHOR]

Liquid crystal is a material which is between solid and liquid phase and commonly called mesophase . Blends of liquid crystal are of great interest because of their unique optical properties. Blending in this study using two monomers of liquid crystal were cholesteryl acrylate and methyl phenyl benzoyl acrylate. The polymerization process using uv curing techniques by irradiation UV ray and without irradiation UV ray. Polymerization of blending liquid crystal acrylate using initiator 2-hydroxy-2-methyl-1-phenylpropane. Based on peak at GPC curve of polymerization by irradiation UV ray, type of that polymer is copolymer. Therefore the polymerization without UV ray, type of that polymer is homopolymer. SEM images of liquid crystal acrylate polymer showed lamella chain models that are characteristic of a polymer chains. Type of polymer liquid crystal acrylate was the type of Side Chain Liquid Crystalline Polymers (SCLCPs). Therefore acrylate polymer liquid crystal in this research has semi-crystalline phase, which contained crystalline phase and amorphous phase on the XRD pattern. The results of FT-IR spectroscopic characterization of the two monomers showed a peak at the wave number of 1600.43 cm -1 and 1622.86 cm -1 which indicates a double bond (C=C) were obtained from acrylation. While the spectroscopy on the product blending the wave number of the peak regions is reduced that shows that carbon double bonds (C=C) in the acrylate group has polymerized. It also strengthened with a very sharp peak for CC functional groups on the wave number of 2855.15 cm -1 . The results of this study indicate that the liquid crystal polymer acrylic polymerization results with radiation UV ray and without UV ray, respectively absorb light in the UV wavelength region 363 nm and 351 nm. [ABSTRACT FROM AUTHOR]

Objectives The aim of this research was to investigate the effects of heat treatment of polymethyl methacrylate powder on mechanical properties of denture base resin. Methods PMMA powder was applied after heat treatment at 100 °C for 2 h (code: HT100) or 130 °C for 2 h (code: HT130). The test specimens were fabricated from autopolymerizing resin to investigate the flexural properties of denture base resin cross-linked with methacrylated dendrimer, the surface microhardness of PMMA beads, and the thickness of the swollen layer of PMMA beads. The specimens were autopolymerized, and all specimens were stored in 37 °C water for 24 h. Half of the specimens were immersed in 37 °C water for an additional 6 months (water storage period: 24 h and 6 months). The flexural strength and flexural modulus ( n =10/group) were measured with a three point bending test. Statistical analysis was performed using ANOVA and the Newman–Keuls test at a significance level of 0.05. Results Heat treatment and the water storage period had a significant effect on flexural strength. The flexural strength of HT130 showed significantly higher values than in other groups. The surface microhardness of PMMA beads of HT130 showed a significantly greater microhardness than other groups. The thickness of a swollen layer of PMMA beads of HT100 and HT130 was significantly decreased. Conclusions The flexural strength and the surface microhardness were increased after heat treatment at 130 °C. The thickness of a swollen layer of PMMA beads was decreased after heat treatment. [ABSTRACT FROM AUTHOR]

Methylated polycyclic aromatic hydrocarbons (MePAHs), unsubstituted PAHs and AhR-mediated activities were determined in street dust collected from Vietnam and India using a combined approach of chemical analysis and in vitro reporter gene assay. MePAHs and PAHs diagnostic ratios indicated that the main sources of MePAHs in Vietnam were pyrogenic emissions, whereas in India there were mixed sources of pyrogenic and petrogenic emissions. AhR-mediated activities determined by using DR-CALUX assay were observed in urban street dust at mean 40, 29 and 20 ng CALUX-TEQ/g dw for Hanoi, Bangalore and New Delhi, respectively. MePAHs and PAHs contributed only 5% or less to AhR-mediated activity in street dust, indicating the occurrence of unknown AhR agonists. The principal contributors to Theoretical-TEQs among target compounds were methyl benz[a]anthracene, benzo[b]- and benzo[k]fluoranthene. The present study indicates importance of MePAHs in evaluation of toxic risk related to AhR-mediated activity in urban polluted areas. [ABSTRACT FROM AUTHOR]

Various chemicals in the environment always exist as mixtures. Toxicity interaction within mixtures may pose potential hazards and risks to the environmental safety and human health. Recent studies showed that toxicity interaction by ionic liquid (IL) mixtures can be related to a certain component. To identify the component, we developed a novel procedure integrating an up-to-down process with the uniform design-based ray method (UDUD) and applied it into an IL mixture system of four 1-butyl-3-methylimidazolium ILs (simply [bmim]X) where X=Cl−, Br−, CH3OSO3− and CH3(CH2)7OSO3−. It was shown that two mixture rays in the quaternary system exhibited significant antagonistic interaction. In this paper, the UDUD was first employed to design four ternary mixture systems. The microplate toxicity analysis was used to determine the toxicities of various mixtures to a freshwater photobacterium Vibrio qinghaiensis sp.-Q67. The concentration addition was taken as an additive reference to assess the toxicity interactions taking place in mixtures. The results revealed that some ternary mixture rays including [bmim]CH3(CH2)7OSO3 display antagonism while the ternary rays without [bmim]CH3(CH2)7OSO3 exhibit additivity. On these grounds, we again designed all binary mixtures containing [bmim]CH3(CH2)7OSO3, determined their toxicities and assessed toxicity interaction. The results showed that three binary mixture systems produce antagonism. Thus, it may be concluded that [bmim]CH3(CH2)7OSO3 is indeed a key component inducing mixture antagonism. [ABSTRACT FROM AUTHOR]

Studies have shown that some cyclic methyl siloxanes were identified as characterized of persistent, bioaccumulated, toxic, and potential to ecological harm. In this study, we determined methyl siloxanes in seawater, sediment and bottom fish samples collected from marine environment in Northeast China. The mean concentrations of total methyl siloxanes were 46.1 ± 27.2 ng/L, 12.4 ± 5.39 ng/g dry weight (dw) and 5.10 ± 1.34 wet weight (ww) in seawater, sediment and fish, respectively. Very strong and significant correlations (r = 0.94, p < 0.0001) were found in compositions of methyl siloxanes between seawater and sewage, indicating that sewage was the main source of methyl siloxanes in the marine area studied. It was found that the mean value of biota-sediment accumulation factor (BSAF) was.0.716 ± 0.456 for D4, 0.103 ± 0.0771 for D5, 1.06 ± 0.528 for D6 and 0.877 ± 0.530 for D7. [Copyright &y& Elsevier]

The article discusses the structure and synthesis of chlorophyll. Topics discussed include the challenge of controlling the nature of the ring nitrogen during the synthesis, the transformation of methyl pyrrole and carboxaldehyde, the maverick nature of the lactolether, and American organic chemist R.B. Woodward's concept of chlorophyll synthesis.

Highlights: [•] The six reaction channels proceed via indirect mechanisms. [•] The C–H bond close to the –OOH group possesses higher reactivity. [•] H-abstraction from –OOH group should be considered at low temperature. [ABSTRACT FROM AUTHOR]

Abstract: The aim of the present investigation was to isolate and identify the phytochemicals from Semecarpus anacardium seeds and evaluate their activity against Gram positive and Gram negative bacterial strains (Bacillus subtilis MTCC 441, Staphylococcus aureus MTCC 96, Escherichia coli MTCC 1689 and Proteus vulgaris MTCC 742 using well diffusion method). The phytochemicals were isolated using silica gel column chromatography and characterized as catechol derivatives by spectroscopic analyses. The antimicrobial activity of the isolated catechol derivatives I-IV varied according to the dose and bacterial strains tested. Among the four catechol derivatives, catechol derivatives I and IV showed prominent antibacterial activity against both the positive and negative human pathogenic organisms compared to catechol derivatives II, III and tetracycline – a reference antibiotic drug. From these findings, it can be concluded that catechol derivatives I and IV possessed methyl group (CH3) in aromatic ring and no double bond in the aliphatic side chain which was not present in catechol derivatives II and III and they possessed double bonds in the aliphatic side chain and no methyl group in the aromatic ring. These may be the possible reason for showing more inhibitory activity of catechol derivatives I and IV. These results showed the effectiveness of catechol derivatives against tested bacterial strains. Further work is necessary to explore these antimicrobial compounds, which are useful in clinical applications. [Copyright &y& Elsevier]

Highlights: [•] Theoretical mechanisms of CH3OCl/CD3OCl with Cl− are investigated by DFT. [•] Anti-E2 elimination is dominant channel competing SN2 and Syn-E2 channels. [•] Rate constants and kinetic isotope effects are calculated by direct dynamic. [•] Vibrational contribution is the dominant factor for kinetic isotope effects. [ABSTRACT FROM AUTHOR]

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Abstract: The technique of SLMs was used to achieve the facilitated extraction of Cr2O7 2− ions, using methyl cholate and resorcinarene as carriers, widely used for facilitated transport of carbohydrates. For our SLMs, toluene as organic phase and microporous film of PVDF as support. Permeability P and initial flux J 0 were determined for different temperatures and the prepared membranes are highly permeable. The results indicate that values of the parameter J 0 depend on the temperature according to the Arrhenius equation. The activation parameters, (Ea, ΔH ≠ and ΔS ≠ ) for transition state on the association reaction substrate–carrier were determined. The mechanism based on the complexation of the substrate by the carrier and the diffusion of the complex (ST) was developed. Results are used to determine the parameters, association constant K ass and apparent diffusion coefficient D*. All studies show that parameters K ass and D* are changing significantly with temperature factor, and better extraction of Cr2O7 2− ions is possible. [Copyright &y& Elsevier]

Highlights: [•] The hydrogen-abstraction mechanism of the CF2HCOOCH3 +OH reaction was investigated. [•] Two conformers of CF2HCOOCH3 were considered in the kinetic calculation. [•] The individual ICVT/SCT rate constants for each H-abstraction channel were evaluated. [ABSTRACT FROM AUTHOR]

Highlights: [•] The F substituent adjoined to the C atom plays a bigger enhancing role than that to the B atom. [•] The methyl group adjoined to the C atom has an enhancing effect, while that to the B atom has a weakening effect. [•] It is a good makeup for the role of F and methyl groups in hydrogen bonds. [ABSTRACT FROM AUTHOR]

Highlights: [•] Quantum calculations of 2-thiomethyl-1-chloroethane and 4-thiomethyl-1-chlorobutane. [•] Calculations of the kinetic and thermodynamic parameters. [•] Neighboring group participation in thiomethyl chloroalkanes elimination. [•] [1,2] Hydrogen shift through four-centered transition state mechanism. [•] CH3S participation in five-membered TS of 4-thiomethyl-1-chlorobutane reaction. [ABSTRACT FROM AUTHOR]

Highlights: [•] The singlet and triplet potential surfaces of the CH3O2 +F reaction were studied. [•] CH2OO+HF are the major products both on the singlet and triplet potential surface. [•] The reaction should be taking place both on the singlet and triplet potential surface. [ABSTRACT FROM AUTHOR]